PHP中for与foreach的区别分析_php技巧
注意: 除非数组是被引用,foreach 所操作的是指定数组的一个拷贝,而不是该数组本身。因此数组指针不会被 each() 结构改变,对返回的数组单元的修改也不会影响原数组。
1. 自php5起,foreach 还可能遍历对象的属性。
2. 自php5起,foreach 可以很容易地通过在 $value 之前加上 & 来修改数组的单元,此方法将以引用赋值而不是拷贝一个值。
$arr = array(1, 2, 3, 4);
foreach ($arr as &$value) {
$value = $value * 2;
}
?>
输出:$arr=array(2, 4, 6, 8)
注意: foreach 不支持用“@”来抑制错误信息的能力。

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